There is no cure for HIV infection or AIDS in spite of recent advances in antiviral therapy. Furthermore, drug therapy is too expensive for most affected populations. For this reason, there is a commitment to the development of safe, effective vaccines to prevent HIV infection and AIDS worldwide. This study evaluates the immunogenicity and safety of candidate HIV-1 vaccines, based on the canarypox vector termed ALVAC, alone and combined with an MN rgp120 product, at 3 [AS PER AMENDMENT 7/19/01: 5] international sites.